Design of cooled infrared bionic compound eye optical system with large field-of-view

Abstract

A multi-aperture compound eye infrared optical system is designed for the imaging of cooled medium wave infrared detector. The optical system includes an infrared lenslet array arranged on the front spherical surface, and a relay infrared optical system matched with a cooled infrared detector. The problem of matching and connection between the infrared lenslet array arranged on a spherical surface and the relay infrared optical system matching with a cooled infrared detector is solved, and a set of multi aperture infrared bionic compound eye optical system that can match the cooled infrared detector is designed. Through the relay optical system, the focal surface imaged by the curved infrared lenslet array of compound eye is re-imaged on the focal plane of the cooled infrared detector. The waveband of the designed compound eye infrared optical system is 3.7-4.8μm. The total focal length is 3.5mm, the total field of view of the multi aperture compound eye optical system is 108°, the distortion of the full field of view is less than 6%. The design result shows that the image quality of the system with different aperture approaches the diffraction limit, and has the advantages of multi-aperture, large field-of-view, low distortion and ideal image quality.

Research on key technology of cooled infrared bionic compound eye camera based on small lens array

“…A cooled mid-wave infrared detector was selected to minimize the effect of thermal noise, and the optical system was designed to simultaneously realize the conversion of a focal surface into a focal plane and achieve 100% cold diaphragm efficiency. Therefore, the aperture stop of the infrared relay optical system must be set at the position of the detector Dewar cold stop to ensure that they are the same size and in the same position 25 . Due to the fixed position of the exit pupil, the relay optical system adopts a special imaging structure to realize the matching and connection with the small lens array, with the first stage being the 61 infrared small lens arrays on the front spherical surface and the second stage being the one connected to the lens arrays and the cooled detector.…”

Research on key technology of cooled infrared bionic compound eye camera based on small lens array

“…When designing the optical system, it is necessary to simultaneously convert the curved focal surface to a flat focal plane and achieve 100% efficiency of the cold stop. Therefore, the aperture stop of the infrared relay optical system needs to be positioned at the location of the detector's dewar cold stop to ensure equal size and consistent positioning 23 . Due to the fixed exit pupil position, the relay optical system adopts a two-stage imaging structure to match and connect with the small lens array.…”

“…Light passes through the spherical infrared lens array to form images, and the spherical images formed by the shell lens array are further imaged on the focal plane of the cryogenic infrared detector through the relay optical system, forming untreated raw scene images. The overall optical system design has a total field distortion of less than 6% 23 .…”

“…The focal length of each ommatidium is 10 mm, the field of view is 28 • , the outer diameter of the ommatidium is 8 mm. Each infrared ommatidium consists of three small lenses, and the optical materials are conventional infrared optical materials such as silicon, zinc sulfide, chalcogenide glass, etc 23 . Nine ommatidia are distributed at the spherical equatorial position.…”

“…To correct large-field curvature, astigmatism, vertical chromatic aberration, and other aberrations, the relay optical system introduces two thick lenses to adjust field curvature and distortion, achieving chromatic aberration balance. The exit pupil of the system coincides with the cold stop of the detector, matching in size and achieving 100% efficiency of the cold stop 23 .…”